The FFSW from KITAGAWA INDUSTRIES America, Inc. is a Microwave Absorber with Frequency 100 KHz, Thickness 0.004 Inch/0.1 mm, Thickness 0.004 Inch, Thickness (mm) 0.1 mm, Magnetic Permiablitity 380 u. Tags: Ferrite. More details for FFSW can be seen below.